#include<iostream>
using namespace std;
int main()
{
int T;
cin >> T;
for(int i = 0; i < T; i++)
{
long double ans = 1;
long double w,e;
cin >> w >> e;
int tmp = w;
for(int j = 1; j <= w; j++)
{
ans *= (e / tmp);
e--;
tmp--;
}
cout << ans << endl;
}
return 0;
}
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